A double blinded randomized controlled trial with rituximab – immunomodulatory treatment of Schizophrenia spectrum disorder in adults

Recent studies strongly suggest that immunological factors are assumed to be determinants for some psychiatric disorders, including schizophrenia, thus anti-inflammatory drugs are promising. However, studies on such treatments are scarce. Rituximab (anti-CD20 antibodies), a standard treatment for multiple sclerosis, is an inflammatory modulating drug.

In our open pilot study (Örebro 2019-2022), we have treated markedly ill, treatment-resistant patients with schizophrenia spectrum disorder (SSD, n=9) with a single dose rituximab (1000mg) as add-on treatment.

Our yet unpublished data (under review) reveal large improvements in all types of psychotic symptoms, with negligible side-effects in almost all the patients.Subsequently, due to the evident positive effect of rituximab in SSD patients, we aim to validate rituximab in a randomized placebo-controlled double-blinded, add-on treatment, in 104 patients (18-51-years) with SSD from 9 Swedish regions.

The primary outcome measure at 12 weeks, is treatment response, defined as clinically relevant reduction in the validated measure PANSS.

Secondary outcomes are Clinical Global Impression – Improvement and Severity scales, the Personal and Social Performance Scale (PSP) measuring overall disability, and a measure of patient self-rated health (VAS scale). Patients are followed for 6 months.

If the treatment is proven helpful compared to placebo, the study may transform the treatment of the entire patient group with SSD.